I'm currently working with gloox in order to send XMPP messages from my C++ program. I work in local network with my private prosody XMPP server.
Sending text messages between two client works but not files. I tried the gloox examples (ft_rcv & ft_send) but it did not worked neither (obviously I modified the examples to match my configuration), I always have the same error :
<error type='cancel'><service-unavailable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
At the beginning I thought it was due to my prosody server but I added the following lines in the conf files :
Component "proxy.jabberserver.local" "proxy65"
proxy65_address = "proxy.jabberserver.local"
proxy65_ports = { 7777 }
I tried different server and different port but I'm currently in a dead end. If someone have an idea it would be great.
Thank you
f->addStreamHost( JID("proxy.jabberserver.local"), "proxy.jabberserver.local", 7777 ); should do the trick. If no - show full XML log.
Related
Good day. I apologize for asking for obvious things because I'm writing in PHP and I know Python at the level "I started learning this yesterday". I've already spent a few days on this - but to no avail.
I downloaded twisted example of the SSH server for version 20.3 from here https://docs.twistedmatrix.com/en/twisted-20.3.0/conch/examples/. Line 162 has an execCommand method that I need to implement to make it work. Then I noticed a comment in this method "We don't support command execution sessions". Therefore, the question: Is this comment apply only to the example, or twisted library entirely. Ie, is it possible to implement this method to make the example server will work as I need?
More information. I don't think that this info is required to answer my questions above.
Why do I need it? I'm trying to compile an environment for writing functional (!) tests (there would be no such problems with the unit tests, I guess). Our API uses the SSH client (phpseclib / SSH2) by 30%+ of endpoints. Whatever I do, I had only 3 options of the results depending on how did I implement this method: (result: success, response: "" - empty; result: success, response: "1"; result: failed, response: "Unable to fulfill channel request at… SSH2.php:3853"). Those were for an SSH2 Client. If the error occurs (3rd case), the server shows logs in the terminal:
[SSHServerTransport, 0,127.0.0.1] Got remote error, code 11 reason: ""
[SSHServerTransport, 0,127.0.0.1] connection lost
I just found this works:
def execCommand(self, protocol, cmd):
protocol.write('Some text to return')
protocol.session.conn.sendEOF(protocol.session)
If I don't send EOF the client throws a timeout error.
I am new to gRPC framework, and I have created a sample client-server on my PC (referring to this).
In my client-server application I have implemented a simple RPC
service NameStudent {
rpc GetRoll(RollNo) returns (Details) {}
}
The client sends a RollNo and receives his/her details which are name, age, gender, parent name, and roll no.
message RollNo{
int32 roll = 1;
}
message Details {
string name = 1;
string gender = 2;
int32 age = 3;
string parent = 4;
RollNo rollid = 5;
}
The actual server and client codes are adaptation of the sample code explained here
Now my server is able to listen to "0.0.0.0:50051(address:port)" and client is able to send the roll no on "localhost:50051" and receive the details.
I want to see the actual binary data that is transferred between client and server. i have tried using Wireshark, but I don't understand what I am seeing here.
Here is the screenshot of wireshark capture
And here are the details of highlighted entry from above screenshot.
Need help in understanding wireshark here, Or any other way that can be used to see the binary data.
Wireshark uses the port to determine how to decode the communication, and it doesn't know any protocol associated with 50051. So you need to configure it to treat this as HTTP.
Right click on a row and select "Decode As..." in the context menu.
Then set "Current" to "HTTP" or "HTTP2" (HTTP will generally auto-detect HTTP2) and hit "OK".
Then the HTTP/2 frames should be decoded. And if using a recent version of Wireshark, you may also see the gRPC frames decoded.
The whole idea of grpc is to HIDE that. Let's say we ignore that and you know what you're doing.
Look at https://en.wikipedia.org/wiki/Protocol_Buffers. gRPC uses Protocol Buffers for it's data representation. You might get a hint at the data you're seeing.
Two good starting points for a reverse engineer exercise are:
Start simple: compile a program that sends an integer. Understand it. Sniff it. Then compile a program that sends a string. Try several values. Once you understand it, pass to tacke the problem of understanding how's google sending your structure.
Use known data and do small variations: knowing what 505249... means is easier if you start knowing the data you're sending (as an example, send "Hello world" string; then change it to "Hella world"; see what changes on the coded sniff; also check that sending several times the same data produces the same sniffed output). Apply prior point: start simple, first empty string, then " ", then "a", then "b", etc. and then pass to complex and larger strings. Don't be affraid to start simple.
GDB Client:
NetworkClientConnect 503: Attempting host: 10.23.37.155 (addr: 02CE4B50)
NetworkClientConnect 518: Connected to host: 10.23.37.155
NetworkClientRecv 576: Recv Packet: +
NetworkClientSend 550: Sent Packet: +
GDB Server:
Debug: 243 275 pld.c:207 handle_pld_init_command(): Initializing PLDs...
Info : 244 22937 server.c:83 add_connection(): accepting 'gdb' connection from 3333
Debug: 247 22954 gdb_server.c:260 gdb_get_char_inner(): received '+'
Debug: 248 22954 gdb_server.c:272 gdb_get_char_inner(): returned char '+' (0x2b)
Initially the connections are made then they acknowledge that they got the packet by sending "+". In my case the client says it is receiving a '+' and so does the server as the very first info exchange. That does not make sense. One has to send and the other receive what I see is both receiving and sending in parallel. But it is working. So where is my thinking wrong? Also if you can point me to a URL which shows exactly the GDB Server and Client protocol exchange that would be awesome.
In your GDB client printout, it looks to me, messages are not printed in order (see that Recv packet has number 576, and sent 550).
Use wireshark or similar tool to debug an issue like this.
I tried connecting to gdbserver via loopback and according to wireshark the dialogue looks like this:
client sends "+"
client sends "$qSupported:multiprocess+;xmlRegisters=i386;qRelocInsn+#b5"
server sends "+"
server sends "$PacketSize=3fff;QPassSignals+;..."
and so on.
Gdb does help an option selectable at runtime that can help debug such things. Start it, then issue "set debug remote 1". Same on remote side. Start gdbserver by "gdbserver --remote-debug ...". This will print remote gdb protocol dialogue on both sides.
Another, possibly best if most time consuming options is to check the gdb&gdbserver source.
I got into WireShark Help Forum (http://ask.wireshark.org/) and posed the question there. "How to capture packets between 2 IP's". There a person called Quadratic gave a brilliant answer. You can refer the WireShark site or here it is. It works like a charm!!
Do this:
• When you first start Wireshark, click on the button in the far upper-left that says "List the available capture interfaces" when you scroll over it.
• In the new "Capture Interfaces" window that opens, select the interface you want to capture packets (with the check box on the left-hand side) and click"Options".
• In the Capture Options window, on the lower-left corner there should be a "Stop Capture Automatically After..." seciton. Check the "packets" option and put in a value of 50
• In the same Capture Options window, in the text box to the right of "Capture Filter", type the statement (without quotes) "ip host 10.xx.xx.xx and ip host 10.yy.yy.yy".
• Hit the Start button :)
One small thing to note - if the interface you're capturing is doing vlan tagging, replace the capture filter statement to "vlan and ip host 10.xx.xx.xx and ip host 10.yy.yy.yy" without quotes.
Edit:
An even simpler solution is to just use one command line statement:
C:\Program Files\Wireshark\dumpcap.exe -c 50 -i {interface name or number} -w {wherever you want to save the packet capture file}
I have established connection to a Siemens S7-300 PLC (simulated via PlcSIM) using the libnodave library. There are no issues connecting and writing data to the PLC. However, I am unable to change the status of the PLC from Start/Stop. I am attempting to use the following libnodave methods for such actions:
int daveStatus = daveStart(dc);
int daveStatus = daveStop(dc);
Both function calls return the same Error: 33794
nodave.c Cites the error as the following:
case 0x8402: return "CPU already in RUN or already in STOP ?";
The use of the daveStart() and daveStop() functions can be viewed in the example testS7online.c:
if(doStop) {
daveStop(dc);
}
if(doRun) {
daveStart(dc);
}
In the examples the start/stop functions are only called when MPI connections to the PLC are made. Does anyone know if the start/stop functions are supported for use with TCP connections? If so, any suggestions as to what may be causing my error?
I have just tried dc.start() and dc.stop() using libnodave 8.4 and NetToPlcSim tool. It worked perfectly. Possibly you don't use NetToPlcSim tool that makes connection to PLCSim via TCP/IP (that is 127.0.0.1 port 102 obviously) hence dc can't even connect. So if your lines don't work, then u must be doing something wrong.
Hello -- I need a simple example to help me understand how to write a Python client and C++ server. Can someone help me find an example of how to send hello world from a server running C++ to Python client? I tried searching Google and other websites for several hours and couldn't find a single example on how to send a parameter through tcp/ip.
Have a look at this http://www.cs.utah.edu/~swalton/listings/sockets/programs/part2/chap6/simple-server.c, It is a simple echo server that accepts connections on port 9999 and echos received message.
For python side this is not very hard, look at this example:
import socket, time
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(('localhost', 9999))
print client.send('Hello world!'), 'bytes sent.'
time.sleep(0.2)
print 'Received message:', client.recv(1024)
use zeromq lib.. .
c++ example of 'hello_world' for server and client are at :
http://zguide.zeromq.org/cpp:hwserver ,
http://zguide.zeromq.org/cpp:hwclient
respectively.. .
and in python.. . study the examples available at github.. .
https://github.com/zeromq/pyzmq/tree/master/examples
Well for my own purpose i am using python for both end.. .Also for more tutorial watch this pycon video
http://blip.tv/pycon-us-videos-2009-2010-2011/pycon-2011-advanced-network-architectures-with-zeromq-4896861
also there is another nice tutorial at http://blog.pythonisito.com/2012/08/distributed-systems-with-zeromq.html